The present disclosure relates to a power transmission apparatus including a transmission, a case that accommodates the transmission, and a counter drive gear to which power from the transmission is transmitted.
Conventionally for this type of power transmission apparatus, a power transmission apparatus is known that includes a speed change mechanism having a multi-plate friction type brake capable of fixing a sun gear of a speed reducing planetary gear to a transmission case so that the sun gear is not rotatable, a counter drive gear to which power from the speed change mechanism is transmitted, a counter driven gear that meshes with the counter drive gear, a drive pinion gear integrated with a countershaft and fitted through a spline to the counter driven gear, and a center support that is fastened to the transmission case with a bolt and that supports the counter drive gear so that the counter drive gear is rotatable (see e.g., JP 2002-349683 A). A brake drum constituting the brake of the power transmission apparatus includes a radial flange portion extending from one end in a radially inward direction. An inner circumferential portion of the radial flange portion has inner circumferential teeth. By fitting the inner circumferential teeth to protrusions formed on a wall surface of an outer circumferential portion of the center support, the brake drum is fixed to the center support so as not to be rotatable. The center support includes a boss portion that rotatably supports the counter drive gear via a bearing, and a wall portion that is extended radially outward from the boss portion and that is fastened to the transmission case with a bolt. A cutout portion is formed in the wall portion of the center support to avoid interference with the counter driven gear.